Mac mail weirdness: signature and truncated messages

1. Sometimes when I hit reply to a message from within the viewer window it truncates most of the email message history. Then when I open the email message and hit reply it doesn't do the truncation. Sometimes this happens, not always. Weird.

2. I use a CSS signature (with small image) for 1 of my email accounts by default. Sometimes the signature is appended to my email automatically, but most of the time it doesn't get appended. Weird (and annoying).